This disclosure relates to cosmetic devices, and in particular to eyebrow shaping techniques and related devices. The Golden Ratio is often denoted by the Greek letter φ (‘phi’). It expresses a relationship that the sum of two quantities is to the larger quantity as the larger is to the smaller (its numerical approximation is 1.618033989). The Golden Ratio is a proportion universally found in Nature, expressed in the arrangement of branches along the stems of plants, in the placement of the shell spirals in snails, or in the features of the human body. The Golden Ratio is widely believed to be a natural principle related to the laws of equilibrium. Many great artists have proportioned their works according to the Golden Ratio, as it is believed to be aesthetically pleasing. Hence, a “perfect” face would display Golden Ratio proportions such as these: Distance from Top-of-the-head to Chin divided by Width-of-head equals φ; Length-of-Lips divided by Width-of-Nose equals φ; Outside distance between Eyes divided by Length-of-Lips equals φ; etc. It follows that, on a “perfect” face, the high point (HP) of the eyebrow would divide the eyebrow arch at precisely the Golden Ratio point between the starting point of the eyebrow (SP) and the ending point of the eyebrow (EP) (SP-to-HP divided by HP-to-EP=φ).